TOKYO — The operator of Japan’s tsunami-crippled nuclear plant said early Thursday that it had almost completed a new power line that could restore electricity to the complex and solve the crisis that has threatened a meltdown.
Tokyo Electric Power Co. spokesman Naoki Tsunoda said the power line to Fukushima Dai-ichi is almost complete. Officials plan to try it “as soon as possible” but he could not say when.
The new line would revive electric-powered pumps, allowing the company to maintain a steady water supply to troubled reactors and spent fuel storage ponds, keeping them cool.
Meanwhile, Japan's nuclear crisis intensified Wednesday after authorities announced that a second reactor unit at the stricken Fukushima plant in northeastern Japan may have ruptured and appeared to be releasing radioactive steam.
The break, at the No. 3 reactor unit, worsened the already perilous conditions at the plant, a day after officials said the containment vessel in the No. 2 reactor had also cracked.
Such were the radiation levels above the plant, moreover, that the Japanese military put off a highly unusual plan to dump water from helicopters — a tactic normally used to combat forest fires — to lower temperatures in a pool containing spent fuel rods that was overheating dangerously.
At the same time, the reactor's operator, Tokyo Electric Power Co., said it had been able to double the number of workers at the plant to 100 from 50. It was not immediately clear when the additional workers returned to the plant.
The vessel that possibly ruptured Wednesday had been seen as the last fully intact line of defense against large-scale releases of radioactive material from the stricken reactor, but it was not clear how serious the possible breach might be. The implications of overheating in the fuel rod pool, which is also at the No. 3 reactor, seemed equally dire.
The developments were the latest in Japan's swirling tragedy since an earthquake and tsunami struck the country with unbridled ferocity last Friday. Emperor Akihito told the nation Wednesday he was “deeply worried” about the nuclear crisis.
The company operating the reactors had withdrawn most of its workers from the plant Tuesday, leaving only a skeleton crew of 50 struggling to lower temperatures.
When those workers were forced to suspend cooling operations, the spent fuel rod pool began heating up dangerously.
Earlier, Japanese broadcasters showed live footage of thick plumes of steam rising above the plant.
Such is the growing international alarm about the nuclear crisis that France announced it was urging its citizens living in Tokyo to head to safer areas or to leave the country — apparently the most urgent instruction offered by foreign countries that so far had largely limited their advisories to simply avoid nonessential travel.
Yukio Edano, the chief cabinet secretary, said the government believed the steam was coming from the No. 3 reactor, where an explosion Monday blew out part of the building surrounding the containment vessel.
The reactor has three layers of protection: that building; the containment vessel; and the metal cladding around fuel rods, which are inside the reactor. The government has said that those rods at the No. 3 reactor were most likely already damaged.
A spike in radiation levels at the plant as the steam was rising forced some of the relatively few workers left at the plant to retreat indoors, suspending some critical efforts to pump water into several reactors to keep them cool.
Earlier, the company that runs the plant reported that a fire was burning at a different reactor, just hours after officials said flames that erupted Tuesday had been doused.
A government official at Japan's nuclear regulatory agency soon after said that flames and smoke were no longer visible, but he cautioned that it was unclear if the fire, at the Reactor No. 4 building, had died out. He also was not clear if it was a new fire or if the fire Tuesday had never gone out.
There are a total of six reactors at the plant. This report includes material from the Associated Press.
